Art of coloring wood.



.W. A. HALL.

ART OF COLORING WOOD.

APPLIOATION TILED MAY 7, 190a.

. 939,015 Patented Nov. 2, 1909.

VV/Yl VESSES UNITED STATES PATENT OFFICE.

WILLIAM AUGUSTUSHALL, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN MAHOGANY COMPANY, A CORPORATION OF MAINE.

ART OF COLORING WOOD.

Specification of Letters Patent.

Patented Nov. 2, 1909.

Application filed May 7, 1908. Serial No. 431,531.

To all whom it may concern:

Be it known that I, WILLIAM A. HALL, a citizen of the United States residing at New York, in the county of New York and State of New York, have invented or discovered certain new and useful Improvements in the Art of Coloring Wood, of which the followin is a specification, refererence being had t erein to the accompanying drawing.

This invention relates to the art of transforming or coloring wood so as to produce, from some of the cheaper or more common woods, products of very attractive appearance, and which will be very desirable for cabinet work and other uses.

The present improvement is more especially applicable to woods, such as oak, chestnut, etc., which contain considerable tannin which, when acted upon by ammonia gas, will cause the wood to be colored to a rich, dark brown, this gas being caused to thoroughly permeate the wood being treated so as to color the same throughout.

The accompanying drawing is a somewhat diagrammatic View of an apparatus by which the invention may be carried into effect.

Referring to the drawing A, B, denote cylinders, which may be of any suitable size and which will be provided with doors, capable of being tightly sealed, and which, when opened, will permit the lumber which is to be treated to be inserted or removed; such lumber being preferably in the form of fiitches, lanks, or boards. These cylinders are pre erably provided at their bottoms with steam ipes or coils C to be connected with any suitable source of steam su ply, as mains C, so that the cylinders may be heated by steam.

D denotes an air pump connected by pipes a and b with the cylinders A and B, respectively. Said pump is also connected by a pipe F with ipes a and b which also communicate wit the cylinders A and B. The pipe F also communicates with a vent pipe 1 provided with a suitable valve F and the pi es a, b, a and b are also preferably provi ed with suitable valves a, h a and b respectively. The cylinders A and B will preferably be connected with a suitable tank or tanks, as E, preferably containing liquid ammonia gas under heavy pressure.

In practicing the invention the seasoned or well-dried lumber to be treated is placed 1n the cylinders A and B, and that one of the said cylinders which is first to be used, say cylinder A, is then preferably moderately heated by admitting steam to the coils or pipes C to expand the air in the wood and thus make the withdrawal of the air from the wood by vacuum treatment more easy. The air pump is then operated to create .a vacuum of 25 inches, or. thereabouts, to withdraw the air from the wood, the air thus withdrawn being exhausted at the vent pipe F. The tanks or cylinders E will preferably be heated, in any suitable manner, as by steam pipes or coils, or otherwise, before admitting the gas therefrom to the cylin ders A and B. If this be not done ice is liable to form in the valves, resulting from intense cold produced by the passage of the gas into the vacuunnand the formation of an objectionable liquid on the wood may also result. Ammonia gas is then admitted to the cylinder from 'atank E, and a pressure is applied to the cylinder, either through the pressure of the gas from the tank E or by pressure created by the air pump D. This pressure need not be very heavy at first, as a preliminary pressure of ten pounds or so tothe square inch will be sufficicnt. The gas pressure in the cylinder containing the wood is then increased to from 50 to 200 )ounds to the square inch, and this will preierably be accomplished by a further hcatin of the cylinder A to expand the gas therein. This pressure and the suction of the wood due to the previous vacuum treatment will cause the ammonia gas to permeate the wood throughout; filling thepores, and by acting on the tannin or tanmc acid contained in the wood the atter will be colored throughout to a rich brown, resen'ibling what is known as antique or cathedral oak. The pressure in the cylinder, to force the gas into and throughout the wood, will be continued for a period of from one to several hours, according to the thickness of the lumber. When the treatment of the lumber in cylinder A has been completed the ammonia gas in said cylinder may be admitted to cylinder B which will also preferably be heated and from which the air has been exhausted by the air pump, and pressure will then be applied to cylinder B in the same manner as above described as to cylinder A, to force the ammonia gas throughout the lumber 1 contained in said linder; and while the lumber in cylinder is being treated cylinder A ma be char ed with new lumber, as may also e done with cylinder B when the lumber in cylinder A is being treated. Thus by employing two communicating cylinders the ammonia as may be used over andover, with a resufting economy, both in gas and time, as well as labor, although of course the two-cylinder mode of treatment is not positively necessary in carrying the novel process .into effect.

In some instances and for some purposes, it will be found desirable to remove, as nearly as possible, all the gas from the wood by vacuum or suction treatment, and the advantages of this will be two-fold; first, in order-to utilize all of the gas, for the purposes of economy, and, vsecond, to get the surplus ammonia gas out of the wood to render the latter fit for immediate use, as otherwise a stron and pungent odor of ammonia will exhale rom the wood, and this would be objectionable. Also, in some cases, free ammonia gas in the wood may be deleterious to the finish to be applied to the wood.

Thus by'the use of two communicating cylinders, as above described,'the same gas may be used alternately inthe cylinders, and 'what little waste of gas may occur can be supplied or compensated for by gas drawn from the tanker tanks E. Also the use of two cylinders permits one to be charged with fresh lumber while the lumber is belng treated in the other, resulting in economy of time and labor, as well as of gas, as above stated. Also the use of two'cylinders permits the gas which may be extracted from the treated wood in one cylinder by the vacuum pump to pumped directly over into the other cylinder by the same vacuum and force pump; thus providing against loss of the as thus extracted.

Havin fims described my invention I claim and desire to secure by Letters Patent:

1. The herein described process for coloring lumber containing tannin, consisting in forein heated ammoniacal gas into and throng out the Wood by pressure, so that the action of the said gas on the tannin in the wood will color the same chemically throughout.

2. The herein described process for coloring lumber containing tannin, consisting in subjecting the wood to a vacuum process, in a closed receptacle, to exhaust the air therefrom, and then forcing an ammoniacal gas into and throughout the wood, by ressure, thus causing such gas to permeate t e wood throughout, so that the action of the said gas on the tannin in the wood will color the same chemically.

3. The herein-described process for coloring wood containing tannin, consisting in heating the wood in a closed receptacle gas from the wood by ically, such forcing of the ing wood containing tannin,

throughout tocolor the same chemically by actin on the tannin.

4. he herein described process for colorin wood containing tannin, consisting in su ectin the wood to vacuum treatment to exhaust t e air therefrom, then forcing ammoniacal gas into the wood, thereby causing such gas to permeate the wood throughout to color the same chemically b acting on the tannin, and then exhausting the ammoniacal a second vacuum treatment.

5. The herein described process for color- Q ing wood containing tannin, consistin in heatm the wood in a closed reeeptac e to expan the air contained therein, then sub- .jecting the wood to vacuum treatment to exhaust the air therefrom, then forcing ammoniacal gas into the wood by pressure, thus causin such gas to permeate the wood throng out to color the same chemically by acting on the tannin, and then exhausting the ammoniacal gas from the Wood by a second vacuum treatment.

6. The herein described process for coloring lumber containing tannin, consisting in forcing previously heated ammoniacal gas into and throughout the wood, by pressure, so that the action of the said gas on the tannin in the wood will color the same chemasinto and throughoutvthe wood being e ected by expanding the gas in the receptacle conta ning previously warmed ammoniacal gas into the a wood by pressure, thereby causing such as to permeate the wood throughout to co or the same chemically by acting on the tannin.

8. The herein described process for colorconsisting in heatin the wood in a closed rece tacle to expan the air contained therein, t en sub- 'ecti,ng the wood to vacuum treatment to exaust the air therefrom, and then forcing thus causing such gas to permeate t e wood throughout to color the same chemically by acting on the tannin, such. pressure for the permeation of the wood by the gas being effected by expanding the gas, in the receptacle containing the wood, by heat.

9. The herein described process for colorin lumber containing tannin, consisting in su jecting the wood to a vacuum process in ammoniacal gas into the wood by ressure,

a closed receptacle to exhaust the air thereaction of the said gas on tie tannin in the wood will color the same chemically, such pressure for the permeation of the wood by the as being eflected by expanding the gas,

in the receptacle containing the wood, by

eat.

10. The herein described process for coloring wood containing tannin, consisting in employing two communicating receptacles or cylinders in which the wood to be treated is confined, subjecting the wood to the action of a vacuum treatment to exhaust the air therefrom, then sub'ecting the wood to the action of ammoniaca underpressure 111 one of the said receptac es or cylinders in which the gas is caused to permeate the wood throu hout, and thenextracting the gas from t e treated wood by a second vacuum action and pumping the gas thus extracted from the treated wood over into the other receptacle or cylinder, thus providing against loss of the gas,

In testimony whereof I alfix my signature, in presence of two witnesses.

' WILLIAM AUGUSTUS HALL. Witnesses:

C. M. SWEENEY, J. D. KLINGE. 

